gpt-5.3-codex works in codex exec but fails in codex mcp-server subagent with same profile/auth
Resolved 💬 3 comments Opened Feb 16, 2026 by MarlonKr Closed Aug 26, 2026
💡 Likely answer: A maintainer (github-actions[bot], contributor)
responded on this thread — see the highlighted reply below.
What version of the Codex App are you using (From “About Codex” dialog)?
26.212.1823
What subscription do you have?
pro
What platform is your computer?
Darwin 25.1.0 arm64 arm
What issue are you seeing?
gpt-5.3-codex works for normal Codex CLI runs, but fails when the same project is invoked as a subagent via codex mcp-server.
Environment
- Codex CLI:
codex-cli 0.93.0 - Auth:
codex login status=>Logged in using ChatGPT - OS: macOS
- account has access to
gpt-5.3-codex - tried with and without forced_login_method
Relevant config
Global ~/.codex/config.toml:
model = "gpt-5.3-codex"
forced_login_method = "chatgpt"
[profiles.subagent-medium]
model = "gpt-5.2-codex"
forced_login_method = "chatgpt"
[mcp_servers.CODEX_PROJECTS_SUBAGENT]
command = "codex"
args = ["--profile", "subagent-medium", "mcp-server"]
cwd = "/Users/.../xyz_agent"
Project <project>/.codex/config.toml:
model = "gpt-5.3-codex"
forced_login_method = "chatgpt"
[profiles.subagent-medium]
model = "gpt-5.3-codex"
forced_login_method = "chatgpt"
What steps can reproduce the bug?
- Configure project + global config as above.
- Confirm auth:
codex login status
- Run normal CLI execution in that project:
codex exec --skip-git-repo-check --profile subagent-medium "reply only: OK"
- Invoke same project via registered MCP subagent (
codex mcp-serverpath), profilesubagent-medium.
What is the expected behavior?
Expected behavior
Subagent call should run with gpt-5.3-codex and succeed, same as codex exec.
Actual behavior
Subagent call fails with:
stream disconnected before completion: The model `gpt-5.3-codex` does not exist or you do not have access to it.
Additional information
- Same subagent works with
gpt-5.2. codex execin the same project shows modelgpt-5.3-codexand starts successfully.
3 Comments
Potential duplicates detected. Please review them and close your issue if it is a duplicate.
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Related design thread: #14039\n\nThis bug feels like a concrete symptom of unclear/fragile subagent model-provider-profile routing semantics. #14039 proposes making that routing explicit and configurable per subagent instead of letting special paths drift.
Note: We've announced that the mcp-server is deprecated and will be removed in a future release. We recommend using the app server interface instead. We won't be prioritizing any bug fixes in the mcp-server, so I'm going to close this issue.